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Biochemistry 2 > E3 Fatty Acid Synthesis > Flashcards

E3 Fatty Acid Synthesis Flashcards

1
Q

the average diet contains plenty of fats needed by the body, therefore there is not a big requirement for FA synthesis. what conditions do require more?

A

embryonic development and lactation

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2
Q

what are some conditions that increase FA synthesis?

A

high carbohydrate diet, alcohol metabolism

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3
Q

what are the primary locations of FA synthesis?

A

liver and adipose tissue

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4
Q

where in the cell does FA synthesis take place?

A

cytosol

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5
Q

T/F. You build FA when you consume excess fat, not carbs.

A

false; excess carbs not fat

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6
Q

you’ve consumed a high sugar meal, what direction are you headed if you do not have enough ATP? if you do have enough ATP?

A

glycolysis

ask yourself if you have enough glycogen

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7
Q

after a high sugar meal, what direction are you headed if you have enough glycogen? if you do not have enough glycogen?

A

FA synthesis

store more glucose

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8
Q

is FA synthesis energy requiring or producing?

A

requiring

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9
Q

is the sodium independent transport system active or facilitated diffusion?

A

facilitated

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10
Q

matching the GLUT transporter to the detail.

A. dietary glucose (intestine --> blood) 
B. muscle and adipose tissue
C. liver, kidney, pancreas
D. stimulated by insulin 
E. insulin independent 
F. stimulated by low energy
  1. GLUT2
  2. GLUT4
A 
A. 1 and 2
B. 2
C. 1
D. 2
E. 1
F. 2
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11
Q

GLUT2 will transport glucose ____ when blood glucose concentration is high.

A

in

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12
Q

GLUT2 will transport glucose out when blood glucose concentration is ____.

A

low

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13
Q

T/F. GLUT4 will act as a glucose sensor in B cell of the pancreas, therefore, stimulating release of insulin when blood glucose is high.

A

false; GLUT2

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14
Q

what will stimulate GLUT4 transporters to relocate to the plasma membrane?

A

insulin and exercise

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15
Q

what will happen to glucose concentration in the muscle if you add a phosphate to glucose?

A

concentration remains low and glucose keeps coming in

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16
Q

what is the role of G-6-P when muscle energy is low? muscle glycogen is low?

A

enters glycolysis, prep step and Krebs to make more ATP

G-6-P can be used to store glucose as glycogen

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17
Q

when glucose is turned away from the muscle and the cell environment changed to high ATP and glycogen stores are full, what is inhibited?

A

PFK (rate limiting step of glycolysis)

first step of glycolysis (hexokinase)

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18
Q

when glucose is turned away from the muscle, where will it go?

A

liver

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19
Q

when glucose is sent to the liver, it will push through glycolysis to produce ATP. what will spill out into the cytosol to provide substrate for fat and cholesterol synthesis?

A

citrate

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20
Q

what organ is the primary site of fructose metabolism?

A

liver

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21
Q

what are the required enzymes for fructose metabolism?

A

fructokinase and triokinase

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22
Q

what intermediate of fructose metabolism stimulates glucokinase?

A

Fructose-1-phosphate

23
Q

does the liver prefer fructose or glucose?

A

fructose

24
Q

what are the ingredients for FA synthesis?

A

acetyl CoA, ATP, NADPH

25
Q

how does acetyl CoA affect FA synthesis?

A

carbons for fatty acid
push through glycolysis and prep-step
aa catabolism

26
Q

what is the reducing power for FA synthesis?

A

NADPH

27
Q

where do we get NADPH for FA synthesis?

A

Pentose Phosphate Pathway

Malate-Pyruvate in cytosol

28
Q

how do we get acetyl CoA from the matrix to the cytosol?

A

the acetyl portion can be transported as citrate

29
Q

what enzyme is responsible for oaa+acetyl CoA –> citrate?

A

citrate synthase

30
Q

what are the reactants for citrate synthase? products?

A

R: oaa and acetyl CoA
P: citrate

31
Q

after citrate is made, we can move to FA synthesis pathway. what are the three steps?

A
  1. citrate moves to cytosol to split back into acetyl CoA via citrate lyase
  2. in the cytosol, FA synthesis is initiated by activating acetyl CoA and converting it to malonyl CoA
  3. FA synthase (ACC) builds new FA 2 carbons at a time
32
Q

what enzyme is responsible for acetyl CoA –> malonyl CoA?

A

acetyl CoA carboxylase

33
Q

does acetyl CoA carboxylase require a co-enzyme? if so, what is it?

A

biotin

34
Q

what reactants are required for acetyl CoA carboxylase?

A

acetyl CoA, CO2, ATP

35
Q

what is the key regulatory and rate limiting step of FA synthesis?

A

acetyl CoA carboxylase (ACC)

36
Q

during short term regulation of ACC, inactive or active ACC is a protomer (subunit)?

A

inactive

37
Q

define polymerization.

A

combining subunits

38
Q

short term regulation of ACC is activate by what? inactivated by?

A

activated by citrate-polymerization

inactivated by LC fatty acyl CoA- depolymerization

39
Q

during short term regulation of ACC, what will phosphorylate and inactivate ACC? dephosphorylate and active ACC?

A

phosphorylate and inactivate: AMPKinase, epinephrine, glucagon
de-phosphorylate and activate: insulin

40
Q

T/F. a high calorie diet/high carb diet will increase ACC synthesis which will increase FA synthesis.

A

true

41
Q

what will stimulate ACC?

A

citrate and insulin

42
Q

what will inhibit ACC?

A

high malonyl CoA, high palmitate, epinephrine, glucagon, AMPKinase

43
Q

what FA synthesis enzyme is a multienzyme complex?

A

FA synthase

44
Q

only a portion of FA synthase is ACP. what is ACP?

A

acyl carrier protein

45
Q

what are the 7 steps of FA synthase?

A
  1. ACP grabs acetyl
  2. ACP transfers acetyl to holding site
  3. ACP grabs malonyl
  4. acetyl and malonyl combine- Condensation (decarboxylation drives the rxn)
  5. ketone is converted to an alcohol -Reduction (NADPH is used)
  6. water is removed- Dehydration
  7. molecule is reduced- Reduction (NADPH is used)
46
Q

what is the end goal of FA synthesis?

A

16C Palmitate

47
Q

what enzyme is responsible for the last step of FA synthesis? what will it do?

A

palmitoyl thioesterase; cleave thioester bond and releases saturated palmitate

48
Q

elongation is accomplished through what enzyme? what does it require?

A

elongase; NADPH

49
Q

desaturation is accomplished through what enzyme? what kind of bonds does it add?

A

desaturase; adds double bonds

50
Q

what enzyme of Krebs is inhibited causing excess citrate to be sent to the cytosol?

A

isocitrate DH

51
Q

what conditions will stimulate FA synthesis?

A

high- energy charge, acetyl CoA, NADH, FADH2, citrate, glucose and fructose
and insulin

52
Q

what are the four key enzymes of FA synthesis?

A
  1. citrate lyase
  2. acetyl CoA carboxylase
  3. fatty acid synthase
  4. palmitoyl thioesterase
53
Q 
matching. 
A. cytosol
B. mitochondria
C. requires NADPH
D. donates 2 carbon units
E. consumes ATP
F. adds 2 carbon units
G. makes ATP 
H. produces NADH and FADH2
I. reactants- acetyl and malonyl ACP
J. reactant- acetyl-CoA
  1. FA synthesis
  2. FA degradation
A 
A. 1
B. 2
C. 1
D. 2
E. 1
F. 1
G. 2
H. 2
I. 1
J. 2

Biochemistry 2 (14 decks)

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